ILLUSTRATIONS 



laginous jaw. The only part of the primary jaw present 

 in the adult is the articular bone. 



65. — Early Embryonic Stages in the Develop- 

 ment OF THE Nose in Man . . . 120 

 (After Keith.) 



C6. — Comparative Anatomy of the Human Palate 121 



A. Recent shark, showing groove from nose to 

 front of mouth. (After Keith.) 



B. Lizard, in which internal opening (choana) 

 from the nose opens in the forepart of the mouth cavity. 

 (After Plate, Allgem. Zool., Gustav Fischer.) 



C. Lion pup with cleft palate, recalling in form the 

 palate of reptiles; showing internal opening of the nose 

 (indicated by the arrow-point) in the forepart of the 

 mouth cavity. In this abnormal specimen the second- 

 ary palate has failed to grow over to the mid-line. 

 (After Keith.) 



D. Human embryo of the end of the sixth week, 

 showing the secondary palatal plates beginning to grow 

 in toward the mid-line and the "primitive choanse" 

 (arrow-point) still exposed in the forepart of the roof 

 of the pharnyx. (After Keith.) 



67. — Longitudinal Section of Head in Young 

 Gorilla (A) and in Man (B), Showing 

 Relation of Tongue to Surrounding Parts 124 

 (After Klaatsch.) 



68. — Longitudinal Section of Lower Jaw of 

 Monkey (A) and Man (B), Showing Attach- 

 ment OF THE Tongue Muscle to the Back 

 of the Jaw ...... 125 



(After Robinson.) 



In B the subdivision of the tongue muscle into strands 

 is over-emphasized in order to show how the upper 

 surface of the tongue could be thrown into diflerent 

 contours by the contraction of different strands of the 

 genioglossus muscle. 



xxviii 



